Swarm. The swarm can occupy another creature's space and vice versa, and the swarm can move through any opening large enough for a Tiny insect. The swarm can't regain hit points or gain temporary hit points.
Actions
Bites. Melee Weapon Attack: +3 to hit, reach 0 ft., one target in the swarm's space. Hit: 10 (4d4) piercing damage, or 5 (2d4) piercing damage if the swarm has half of its hit points or fewer.
How many swarms of wasps for a fight?
A swarm of wasps is worth 100 XP. Using the 2024 encounter budgets (SRD 5.2), this is how many swarms of wasps fit each difficulty for a party of four characters of the same level. A dash means even one would be over the budget.
Party level
Low
Moderate
High
1st
2
3
4
2nd
4
6
8
3rd
6
9
12+
4th
10
12+
12+
Budgets add up every monster’s XP, so you can swap some for other creatures of the same total. Try other party sizes and mixes in the encounter calculator.
How the swarm of wasps compares at CR 1/2
Against the 32 other challenge 1/2 monsters in the SRD 5.1, the swarm of wasps has more hit points than 15 of them, which makes it a little frailer than most at its CR. See every CR 1/2 monster.
